The Portable Commutator was a telecommunications device that was used by the military during World War I. It was manufactured by
Northern Electric Company
Nortel Networks Corporation (Nortel), formerly Northern Telecom Limited, was a Canadian multinational telecommunications and data networking equipment manufacturer headquartered in Ottawa, Ontario, Canada. It was founded in Montreal, Quebec, ...
. It was used as a one-wire
telegraphic switchboard.
References
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Nortel products